1
NEDSP1962-KBD User Installation Manual
1.
Introduction
The NEDSP1962-KBD amplified DSP noise cancelling module can be retrofitted inside many types of
extension speaker or older style radios and transceivers. It incorporates unique Digital Signal
Processing (DSP) technology which can identify speech from within a noisy signal and can provide up
to 40 dB of noise reduction and 65 dB of tone reduction. The module comes pre-wired and with an
on-board power amplifier enabling it to be easily incorporated into existing equipment. All the
module functions are controlled by the pre-wired keyboard switch assembly. The
NEDSP1962-KBD
uses a powerful programmable DSP audio processing chip with DSP noise cancelling technology
inside
. This high−performance chip delivers exceptional sound quality and incorporates a full audio
signal chain with 16−bit A/D converters and di
gital interfaces utilising fully flexible digital processing
architecture. The audio amplifier stage is provided by a Texas Instruments TPA3111D1PWPP Mono
Class-D audio power amplifier chip which is 94% efficient, eliminating the need for heatsinks.
1.1 The NEDSP1962 Module features:
▪
Fully adaptable noise cancellation 9 to 40dB (8 filter levels)
▪
Up to 65% heterodyne tone reduction
▪
Overall Gain control
▪
Input level overload indicator
▪
Easy to install between input and loudspeaker
▪
Frequency Response (50 Hz to 5 kHz)
▪
Up to 7.5 Watts output (4
Ω
)
▪
Noise Reduction can be preset or remotely set during operation
▪
10 to 18 Volts DC supply range
▪
Adjustable audio indicator
“beep” tones
▪
Pcb Mounting Holes
▪
Audio bypassed when power removed
▪
Small Size 70 mm x 50 mm x 12 mm
The NEDSP1962-KBD DSP noise cancelling module is supplied with 1 x 1030-FPL fused DC power
lead, full mounting kit with bhi labels and installation user guide.
1.2
Limitations
This module is designed to pass speech. Other signals such as data, music and morse (CW) will pass
through to some degree depending on the filter level setting, but the integrity of these signals
cannot be guaranteed. This module is designed to be driven from a High-Level signal source capable
of operating into a load of 62
Ω
impedance.
Important Note:
The Audio Output Amplifier is ‘Class D’ and therefore neither of the output wires
should have any connection to ground, they should only be connected to a speaker or a fully
isolated socket for headphones.
1.3
Module connection and mounting
The module comes pre-wired with a 2.1 mm power socket fitted (centre pin +ve). The
“
audio in
”
and
“audio
out
”
connections are pre-wired pairs of wires, ready to be connected into the audio path
